Cream Dilution
Cream is what is known as an incomplete dominant, meaning that it expresses differently in its heterozygous and homozygous forms. Cream affects only red pigment in its heterozygous form, and effects black and red pigment in its homozygous form. There is a genetic test for cream and the designation for a heterozygous cream is CCr, and for a homozygous form is CrCr. A single cream dilute (heterozygous) has a 50% chance of passing on cream to its offspring and a double cream dilute (homozygous) has a 100% chance of passing on cream, regardless of the color of its mate.